I've seen battleaxes cracking left and right lately, I posted mine in a thread recently, and since I have seen major cracking on one mounted on my buddies zx10r, and a concourse. I have a pr4 in the garage now!
5140 miles on the Battlax S20s. No problems with them even in 15 degrees or pouring thunderstorms. Replaced it with PR4s only because had already run on a plugged rear tire for more than 2000 miles. Tread wear showed that I could have gone at least 2000 more- but had cash, so eh.